Clean and clean the mushrooms. Wash tomatoes, dab dry and cut in half. Twist slices of ham. Wash parsley, dab dry and chop coarsely. Beat the eggs and milk. Season with salt, pepper and nutmeg.
Fold in the parsley. Heat the oil in a pan. Sauté the mushrooms in it. Season with salt and pepper. Add tomatoes and ham. Pour egg milk over it and let it simmer at medium heat for about 15 minutes.
Cut the cheese into thick slices and put them on the omelette 5 minutes before the end of the frying time.